A standard slide fastener comprises a pair of symmetrically identical stringer halves each comprising a textile tape to whose edge is fixed a coupling coil. The coil is formed of a row of turns each in turn forming a coupling head that projects from a longitudinal edge of the respective tape toward the other tape and can be interleaved between the heads of the other tape to join the two tapes together. Each turn of the coupling coil comprises, in addition to the already mentioned head, a lower leg lying on the tape, an upper leg offset from the plane of the tape, and a bight joining one of the legs of the turn to the other leg of the adjacent turn, with both legs and the head of each turn normally lying on a common plane perpendicular to the coil. The coil can be secured to the tape by actually having floats or filaments of the tape engaged over the legs so that in effect each coil is knitted into the respective tape.
In U.S. Pat. No. 4,075,874 such a stringer half is described where the coiling coil is secured exclusively by warp chains engaged over the upper legs of the coil. The preformed coil is fed like a weft filament into the tape as the same is knitted. Such a stringer half is easily damaged when kinked or creased and is particularly susceptible to damage when subjected to a transverse stress which can shift the coil in the knitted tape.